Package making – Wrapping machines – Cover-wiping passage or pocket for initial wrap
Patent
1998-11-09
2000-02-01
Sipos, John
Package making
Wrapping machines
Cover-wiping passage or pocket for initial wrap
B65B 1106
Patent
active
060189304
DESCRIPTION:
BRIEF SUMMARY
The invention relates to constructional and functional improvements in the elevators of machines for packaging products with stretchable film, particularly in the systems for varying the active surface of the said elevator and adapting it to the dimensions of the products to be packaged. In particular, the improvements in question are suitable for machines of the type described in EP-A-0 569 615 and EP-A-0 619 227 to which the most ample reference will be made.
In order to provide a clearer understanding of the objects of the invention, it will be useful to note briefly that, in the machines referred to, the stretchable film unwound from the reel is held at the leading edge by a comb dispenser interacting with a movable parallel gripper, also in the shape of a comb, which grips the leading edge of the film and moves away from the dispenser to stretch horizontally a portion of the said film, with a length proportional to the dimensions of the product, in the packaging station. The product to be packaged is fed to an elevator which is located under the said horizontal portion of film and which is formed by a plurality of brackets parallel to each other and to the said dispenser and gripper system and on which are disposed oscillating supports, held in the upright position by elastic means. The product rests on these oscillating supports which are made to drop and are made inactive by the lateral grippers holding the lateral flaps of the said portion of film stretched in the packaging station, when these grippers fold the said flaps under the product by entering the support of the product, while the elevator returns to the low position at the correct time to repeat the operating cycle.
To prevent the interference of the elevator with the movable gripper which stretches the said horizontal portion of film in the packaging station, the parallel brackets which form the said elevator are made to be fitted on and projecting from a transverse shaft fixed to the vertically movable element of the elevator, and some of the brackets, facing the said movable gripper, are made to be oscillating on the said shaft and are provided with a catch which, by elastic means, is normally kept in interaction with the tooth of a cam fixed on the said shaft, to keep the corresponding bracket in the horizontal active position. During the rising phase of the elevator, its brackets which would interfere with the said movable gripper feeding the film interact through their catches with a static lock whose position is determined from time to time directly by the said gripper, so that the said catches are released from the corresponding cams and the corresponding brackets oscillate downwards and are thus removed from interference with the gripper located above. In the subsequent downward travel of the elevator, the brackets which have been made inactive in the preceding operating cycle interfere with a fixed stop which returns them to a horizontal position, while the catches are reset to keep the brackets in the active position.
In the practical use of the machine with the elevator designed in the aforesaid way, it was found that the said elevator was subject to undesirable and harmful vibrations when the catches interacted with the said inactivating lock and when the non-working brackets oscillated downwards, especially since this interaction took place at a considerable speed. The invention is intended to overcome this problem with the following idea for a solution. The catches of the brackets which can be made inactive when necessary, when the elevator is in the lower rest position, are designed to be able to interact with corresponding cams of different angular extents, keyed on a single shaft driven by a motor with electronic speed and phase control, and supported rotatably by the base of the machine. When a product is fed to the elevator and known means measure its dimensions and send them to the processor which then determines the travel of the film unwinding gripper in the packaging station, the said processor causes the cam shaft
REFERENCES:
patent: 4583348 (1986-04-01), Treiber et al.
patent: 4674269 (1987-06-01), Denda
patent: 5528881 (1996-06-01), Cappi et al.
Cappi Angelo
Rimondi Renato
A.W.A.X. Progettazione E Ricerca S.r.l.
Jensen Steven
Sipos John
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